Excalibur supplies the red stone's power: the flames.

Excalibur supplies the red stone's power: the flames. In Sela's encounter with Arthur, he says the Lady in the Lake gave him the sword. He also explains that it was made in inextinguishable flames, which he can call upon when he needs them in battle. The scene shows him doing exactly that. Later, Sela unleashes the fire through Lysraseri herself. The green stone belongs to Kusanagi, the sword earlier called Ame-no-Murakumo. Its contribution is healing for the person holding it. The earlier scene shows an injured swordsman recovering when he gets the blade back into his hands. By the end of the issue, Ordella explicitly explains the healing property to Sela. These are specific abilities attached to the constituent swords. The story isn't saying that every legendary weapon grants healing, or that holding Lysraseri makes someone incapable of dying. What it gives us is a very clear explanation of where two of its powers come from.